Polishing machine



June 3, 1930. c, VAN NORMAN ET AL 1,761,059

' EOLISHING MACHINE Filed Dec.,14, 1928 2 Sheets-Sheet 1 'INVENTOR. 741444, a: 6.4%.,

6. M BY A TTORN June 3, 1930. c, E, NORMAN AL ,7 1,761,059

POLISHING MACHINE 2 Sheets-Sheet 2 Filed Dec. 14, 1928 3 5 1% 5 7 M 0 F7 00 M ENTOR.

r% ATTORNEYST/ Patented June 3, 1930 CHARLES E. VAN NORMAN AND BYRON F.STOWELL, OF SPRINGFIELD, MAS SACHU- SET'IS, ASSIGNORS TO VAN NORMANMACHINE TOOL 00., OF SPRINGFIELD, MASSA- GEUSETTS, A CORPORATION OFMASSACHUSETTS romsnnve MACHINE Application filed December 14, 1928.Serial No. 326,010.

This invention relates to machines for sanding, polishing, or buflingsurfaces. The invention is particularly directed to the production of amachine, light enough for manual use, which will produce a so-calledstraight line rubbing action and which will operate on either plane orcurved surfaces.

The machine previously proposed for polishing varnished or lacqueredsurfaces have been unable to displace hand rubbing because they failedin one or both of two particulars. A machine which does not duplicatethe straight line eflect given by hand rubbing, but instead operates bya generally circular motion of the rubbing surface, gives an inferiorappearance to the article.-::= But even with a straight rubbing action,a success ful machine must be able to duplicate the action of handrubbing in following either a major curvature of the article beingrubbed or minor undulations of the surface which, when properl rubbed,are imperceptible to the eye. We elieve that the machine hereindescribed is the first to produce the effect of hand rubbing in theseparticulars withsufficient similarity to be commercially useful wheregood quality work is desired. The manner in which this desirable resultis attained will appear from the following description and claims.

Referring to the drawings: 7

Fig. 1 is a side elevation of a polishing machine embodying ourinvention;

Fig. 2 is a top plan view thereof; Fig. 3 is an enlarged section on line3-3 of Fig. 2, showing the guides and slides removed from the housing;

Fig. 4 is a section on line 4-4 of Fig. 1; Figs. 5 and 6 are enlargedsections,-on line 5-5 of Fi 1, of one of the slides and one of the rubing pads respectively, showing the pad disassembled from the slide; and

Fig. 7 is a longitudinal section on line 77 of Fig. 4.

The mechanism in its preferred form is supported by and partiallycontained within a housing 10, preferably fitted with a handle 11.Within the housing is mounted an electric motor12 having its shaft 13fitted rotation upon a shaft 16 suitably carried by the housing,-and hasrigidly secured to it a bevel gear 17. Meshing with this bevel gear is asecond bevel gear 18 mounted for rotation upon a vertical shaft 19 alsobearing a spur gear 21. On each side of the spur gear 21, and meshingwith it, are spur gears 22 and 23 carried by vertical shafts 24 md 25bearing at their lower ends crank disks 26 and 27. To these disks aresecured pins 28 and 29 pivoted to connecting rods. 30 and 31. The otherends of these connecting rods are pivoted respectively to pins 32 and 33attached as will be described to slides carrying the polishing pads.While, if desired, one slide only need be used, it is preferred to usetwo slides reciprocatin in opposition in order to balance out troulesome vibration of the device. As these slides are identical, adescription of one only will be given.

Each slide comprises as its main body a strip 35 of leather or othersuitable slightly flexible material, cut away on its sides as at 36. Aflexible metal strip '37, preferably of phosphor bronze, is connected tothe leather strip by rivets 38. The gap at each side formed between thecut away portion 36 and the metal strip serves to receive a steel strip39 joined by rivets 40 with a leather strip 41 lying within flanges 42of the housing 10 and joined thereto by screws 43. The leather strip 41and the steel strip 39, separated by spacing strips'44 preferably offiber, form a guideway upon which the slide, comprising the leatherstrip 35 and the bronze strip 37, slides. The sliding friction duringthe re ciprocation of the slides is taken up by the bearing of thebronze and steel strips on each other. At one end of the leather strip35 a metal plate 45 is inserted, conveniently held in place by rivetingto the metal plate 37, to which the pin 32 is connected in order to jointhe slide with its reciprocating mechanism. The stationary leather strip41 is slotted as at 46 to permit the necessary movement of'the pin.

The rubbing pads are preferably detachabl connected to the slides sothat pads of di erent textures, pads impre ated with differentabrasives, or even sanding surfaces,

may be used as desired with the same operating mechanism. The detachableconnection may be made in any desired manner, but it is desirable fromthe standpoint of ra idity of changing pads, to employ snap asteners,preferably of a rugged type and of fairly large size. The shanks 47 of aseries of these fasteners 48 pass through holes in the metal plate 37and are headed over as at 49. The holes are made somewhat larger thanthe shanks in order to permit a slight amount of side play, useful inaccommodating slight inaccuracies in the positioning of the fasteners ondifferent pads and in facilitating the assembly of the pads with theslides. lhe pads are formed with a felt body 50 adherently secured toleather strips 51. The shanks 52'of snaps 53 mating with the snaps 48pass through the leather and are headed over as at 54 before the feltbodiesare applied.

The leather strips 41 forming part of the guideways are preferablyrigidly held where they are connected with the housing, but they projectbeyond the housing'a considerable distance to form a flexible extensionof the guideway. To increase the flexibility at this point, notches 55may be cut transversely of the strips. The extensions of the guides maybe flexed to cause the similarly flexible slides to follow the contourof the object being.

polished, ribs 56 bein preferably riveted to the leather strips 41etween grooves 55 to facilitate exerting the necessary manual pressurefor this purpose.

In use the device is placed upon the work to be polished and the motorstarted, a switch 57 beln conveniently located in the handle 11 for t ispurpose. The speed of the motor and the design of the associated gearingis such as to reciprocate the slides at a fairly 7 rapid rate. say sevenhundred strokes a minute. Where more than one slide is employed, thecranks are preferably set so that the slides move simultaneously inopposite directions. This completely eliminates any troublesome tendencyfor the device to, jump and creep on the work, due to the balancing ofthe dynamic forces; and also gives to the 'device a very slight wobblefrom side to side which causes any point on the rubbing pad to travel ina very flat figure 8 curve rather than in a straight line. This slightsidewise movement is desirable as it prevents scratchin and causes amoreeven polishing action. f the work is curved, like an automobile fender,or if it possesses slight undulations, like most woodwork, the guidesare curved by manualpressure upon their extended portions so that theslides carrying the rubbing pads are caused to conform to the particularshape of the surface being dealt with. The device will. operate onplane, convex, or concave surfaces with equal facility, provided thecurvature is not too abrupt.

1,7e1,ose

What we claim is: v

1. A olishing machine comprising two sets of exible guideways, a pair offlexible slides one reciprocable in each guideway, rubbing surfacescarried by the slides, and means for-moving the slides simultaneously inopposits directions.

2. A olishing machine comprising two sets of exible guideways, a rigidhousing supporting the guideways over a portioh of their length to avoidflexure while permitting 3. A polishing machine comprising two guidewaysside by side, each guideway being flexible throughout a portion only ofits length, a pair of slides one reciprocable in each of theguideways'and flexible for at least a portion of their length, rubbing sur-' facescarried by the slides, and means for reciprocating the slidessimultaneously in opposite directions.

'4. A polishing machine comprising a housing, guides secured to thehousing and having flexible extensions projecting beyond the housing,flexible rubbing members reciprocable on the guides, a'motor in thehousing, a pair of cranks rotatably mounted in the housing, gearingconnecting the cranks to the motor, and connecting rods joining thecranks to the reciprocable rubbing members, the cranks being mounted inopposition so that the rubbing members are reciprocated simultaneouslyin opposite directions.

5. A polishing machine having a housing, a strip of leather or the likecarried by the housing and projecting beyond it to form a flexibleextension, flexible spacing strips secured to the edges of the leatherstrips, flexible metallic bearing strips secured to the spacing stripsand extending inwardly therefrom,

a slide of leather or the like extending be-,

tween the spacing strips and held by the bear ing strips, a flexiblemetallic bearing strip secured to the leather slide and underlying thefirst-named bearing strips so that upward pressure on the slide isabsorbed by the two sets of bearing strips, a rubbing pad detachablyconnected to the slide, and means'for reciprocating the slide relativelyto the housface and slidable in the guideway, and meohanism forreciprocating the slide. v

8. A polishing machine comprising a flexi-' ble guideway, a rigidhousing supportin the guideway over a portion of its lengt to avoidflexure While permittin flexure in the remainder of the length of tfieguideway, a flexible slide reci rocable in the guideway, and bearing a,ru bing surface, and mecha- 1o nism carried by the housing forreciprocating the slide. I Y

9. A olishing machine comprising a flexible i eway, a rigid housingsupporting the gui eway over a portion of its length to avoid exurewhile permitting flexure in the remainder of the length of the guideway,aflexible slide reciprooable in the guideway, a flexible rubbing paddetachably carried by the flexible slide, and mechanism carried by thehousing for reciprocating the-slide. In testimony whereof we haveafiixed our signatures.

CHARLES E. VAN NORMAN. BYRON F. STOWELL.

